Preparation of Metal Oxide Nanoparticles by Laser Ablation.

Abstract

Nanoparticles of metal oxides such as iron and cobalt oxides were prepared by pulsed laser ablation in Ar ambient at room temperature. The off-axis configuration of target and substrate greatly improved size distribution of the deposited nanoparticles. The morphology, crystallinity and oxidation states of the deposited nanoparticles and the nanoparticle-aggregated films were strongly dependent on the ablation pressure. The continuous and amorphous films consisting of the lower oxides such as FeO and CoO were deposited at lower pressure than 10 Pa. The formations of oxide nanoparticles of highly oxidized and crystallized phase such as Fe2O3 and Co3O4 were observed under the medium pressure range at around 100 Pa. The aggregates of nanoparticles were observed under higher pressure than 267 Pa. The size of the iron and cobalt oxide nanoparticles ranged from 2-9 nm and 2-4 nm, respectively. The basic ideas of growth mechanism are discussed.